Automatic cut sheet feeding unit

ABSTRACT

An automatic cut sheet feeding device provided with a cut sheet box with an open top. The box is provided with a separation pawl facing the inside and located on each end of the upper side of the sheet feeding lateral side, the separation pawls being mounted to allow the box to move vertically to some degree. The bottom surface of the box body is inserted into the space between the lower side and the bottom surface of the arm in order to limit the separation pawls from moving over a certain degree. By said arrangement, the device can feed the cut sheets effectively into the copying device automatically, without requiring an additional guide etc., even when the number of sheets has been reduced.

United States Patent 1191 Komori et al.

[ Nov. 18, 1975 1 1 AUTOMATIC CUT SHEET FEEDING UNIT [73] Assignee: Canon Kabushiki Kaisha, Tokyo,

Japan [22] Filed: May 23, 1972 [21] Appl. No.: 256,125

[30] Foreign Application Priority Data June 4, 1971 Japan 46-46702 June 8. 1971 Japan 46-40415 [52] US. Cl. 271/118; 271/127; 271/160; 271/162; 271/169; 271/170 [51] Int. Cl. B65H 1/12; B65H 3/56 [58] Field of Search 271/39, 61, 62 R, 86, 118, 27l/126,127, 145, 147,162, 160, 171,170, 169; 206/57 R 56] References Cited UNITED STATES PATENTS 1,201,360 10/1916 Schwerotle 271/61 X 1,714,314 5/1929 Neidich 206/57 R 2,381,188 8/1945 Swindle 271/39 2,889,036 6/1959 Davies 206/57 R X 2,922,644 l/196O Perzentka 21 l/17O 3,272,502 9/1966 Beachum 271/160 3,285,601 11/1966 Zevthen 271/61 X 3,520,533 7/1970 Phleps et al. 271/39 3,588,106 6/1971 Casba et al. 271/61 3,599,972 8/1971 Miciukiewicz.... 271/127 3,672,665 6/1972 Schnall et al. 271/39 Primary Examiner-Evon C. Blunk Assistant Exanziner-Bruce H. Stoner, Jr.

Attorney, Agent, or Firm-Fitzpatrick, Cella, Harper & Scinto [57] ABSTRACT An automatic cut sheet feeding device provided with a cut sheet box with an open top. The box is provided with a separation pawl facing the inside and located on each end of the upper side of the sheet feeding lateral side, the separation pawls being mounted to allow the box to move vertically to some degree. The bottom surface of the box body is inserted into the space between the lower side and the bottom surface of the arm in order to limit the separation pawls from moving over a certain degree. By said arrangement, the device can feed the cut sheets effectively into the copying device automatically, without requiring an additional guide etc., even when the number of sheets has been reduced. v

6 Claims, '26 Drawing Figures US. Patent Nov. 18,1975 Sheet1ofl3 3,919,972

U.S. Patent Nov. 18, 1975 Sheet 2 of 13 3,919,972

U.S. Patent Nov. 18, 1975 Sheet40f13 3,919,972

US. Patent Nov. 18, 1975 SheetSof 13 3,919,972

U.S. Patent Nov. 18,1975 Sheet6of13 3,919,972

U.S. Patent Nov. 18,1975 Sheet8of 13 3,919,972

U.S. Patent Nov. 18, 1975 Sheet 9 of 13 3,919,972

FIG. I3

FIG.I4'

US. Patent Nov. 18, 1975 Sheet 10 of 13 3,919,972

FIG. I5

R & v 2 H @150 m0. 1 2lH||11|1LA||||1|||1111|1J\& Elm u 2 .m; 9 9 6 G F FIG. I7

US. Patent Nov. 18,1975 Sheet110f13 3,919,972

U.S. Patent Nov. 18,1975 Sheet 12 of 13 3,919,972

FIG. 22

U.S. Patent Nov. 18, 1975 Sheet 13 of 13 3,919,972

FIG. 23

FIG. 24

AUTOMATIC CUT SHEET FEEDING UNIT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an automatic cut sheet feeding unit used in electrophotographic or various other copying devices or in simple printers. This invention includes, further, the improvement of cassette means used in the automatic cut sheet feeding device.

2. Description of the Prior Art The transfer paper for transfer type copying devices, and the photosensitive paper used in electrofax systems, as well as the printing paper used in simple printers are considered as cut sheets. Heretofore, it was common practice to automatically feed such sheets by positioning them in a cassette and then loading the eassette in the unit. In some cases, a cut sheet box which corresponds to the cassette was permanently mounted on this unit.

An object of this invention is to provide a mechanism to dispense paper, one sheet at a time, assuredly and smoothly from such a cut sheet box.

This invention is directed to a device which automatically feeds the above-mentioned cut sheets effectively into a copying device etc. and does not require an auxiliary guide etc. even when the number of sheets has been reduced. The device feeds the sheet extremely smoothly at all times, and allows the cut sheets and cassette to be easily loaded.

SUMMARY OF THE INVENTION In order to attain the above-mentioned object, a cut sheet box with an open top is provided with a separation pawl facing the inside and located on each end of the upper side of the sheet feeding lateral side. The separation pawls are mounted to the cut sheet box in such a manner as to allow the box to move vertically to some degree.

In order to realize these functions, the sheet feeding lateral side of the cut sheet box is made separately from the box body, and arms are provided on both ends at right angles respectively, and the sheet feeding lateral side is loosely mounted on the box body. A separation pawl is provided facing inward on each end of the upper side of the sheet feeding lateral side, the lower side thereof being bent along the bottom lower surface of the box body, and the bottom surface of the box body being inserted into the space between the lower side and the bottom surface of the arm in order to prevent the separation pawls from moving over a certain degree. However, this invention does not require the separation of the sheet feeding side of the cut sheet box, and, allows the separation pawls to be provided with a stopper, which controls the sheet position of the sheet feeding side.

An intermediate plate, which is smaller than the inside of the box body, is inserted into the box body and, between the intermediate plate and the bottom springs are provided, which are strong enough to push up, by way of the intermediate plate, a specified number of cut sheets, even when the number of sheets is reduced by consumption, and to press the sheets against the separation pawls with the proper force.

This invention offers several embodiments for the cassette mentioned above.

Although there are embodiments in which the feed roller is always placed on the top sheet in the cassette,

the following description is directed to an embodiment wherein the feed roller rotates and depresses the sheet only at feeding time.

The feed roller is supported by an arm provided with a shaft, and is positioned by the force of a spring etc. at a position spaced apart from the paper surface in the cassette box. The feed roller may rotate continuously or just at the time of feeding the sheet. 1

Upon receiving the feed signal, he arm rotates a certain angle and the feed roller is pressed on the upper surface of the stacked sheets. The latter position of this feed roller is always constant, and is set in such a way that the lowest surface of the feed roller is slightly lower than the natural position which the uppermost sheet reaches when the stack of sheets is pushed up by the springs. Accordingly, the separation pawls are always in position to press the sheets by their own weight regardless of the height of the stacked sheets. In other words, the separating action is always the same even when the number of sheets is reduced and thus the feeding of a single sheet is performed with assurance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross section of an embodiment of the invented cassette in a state filled with cut sheets;

FIG. 2 is a longitudinal cross section of the same cassette as shown in FIG. 1, but the number of the cut sheets has been reduced;

FIG. 3 is a perspective view of the cassette box of FIGS. 1 and 2;

FIGS. 4 and 5 are longitudinal cross sections of another embodiment of the cassette means wherein the filing condition of cut sheets has been gradually reduced by consumption;

FIG. 6 is a perspective view of the said cassette box of FIGS. 4 and 5;

FIG. 7 is a longitudinal cross section of an embodiment of the invented automatic cut sheet feeding unit shown in a feeding state;

FIG. 8 is a longitudinal cross section of one portion of said unit in a state of rest;

FIG. 9 is a perspective view, and

FIG. 10 is a plan view of the cassette box;

FIGS. 11 and 12 are longitudinal cross sections of one portion of a copying device mounted with cassette means according to another embodiment;

FIG. 13 is an end view of the device of FIGS. 11 and 12;

FIG. 14 is an enlarged view of the rail section of the body of the copying device and cassette means;

FIG. 15 is a side view of a cassette for large sized paper (for example, size A3);

FIG. 16 is a plan view of the cassette of FIG. 15;

FIG. 17 is an enlarged perspective view of the hinge section of the fixed lid of the cassette;

FIG. 18 is an enlarged perspective view of the engaging section of said fixed lid and the cassette;

FIG. 19 is a side view of a cassette for small sized paper (for example, size A4);

FIG. 20 is a plan view of the cassette of FIG. 19 with the lid removed;

FIG. 21 is a perspective view showing the relationship between the cassette load signalling element and the switch on the main unit;

FIG. 22 is a plan view of another embodiment of cassette means;

FIGS. 23 and 24 are the sectional views taken along the line indicated at IV-IV in FIG. 22;

FIG. 25 is a sectional view taken along the line indicated at VI-VI of FIG. 23; and

FIG. 26 is a perspective view of the embodiment of FIG. 22.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Several embodiments of this invention will be described in detail hereafter with reference to the drawings. The embodiments will be described following the steps of improvement' In the drawings, 1 is a cassette acceptor contained in a copying device, 2 is a cassette box which is mounted on the acceptor I by preferably three legs 3 which are detachably mounted on means 4. The inside of the cassette box 2 must have dimensions, including proper margins, corresponding to the dimensions of cut sheet P and must be deeper than the thickness of the stack of a predetermined number of cut sheets.

An intermediate plate 5 is inserted into the box 2 in such a way as to allow the plate to move freely in the vertical direction. Spring 6 is provided between the front bottom surface of the plate taken in the feeding direction, and the box 2 to make the front end corners of cut sheet P, loaded on the intermediate plate, push against the separation pawls 7 located on the front corners. The lid 8 of the cassette box 2 which, after being loaded on the copying device, is opened at the front lid 8 through the hinge 9 to permit positioning the feed roller 10 in respect of the sheet seizing roller 11. Moreover, a rotary supporting point 12 is provided on the back of the rear end of the intermediate plate, as required.

' In the above-mentioned configuration, a predetermined number of cut sheets are loaded into the cassette box 2 between the separation pawl 7 and the intermediate plate 5, and are compressed by the spring 6. When this cassette box 2 is set at the predetermined position of the acceptor 1 of the copying device as shown in FIG. 2, the separation pawl 7 on the front end takes a predetermined position in respectof the seizing rollers 11, and the feed roller 10 also makes contact with the top out sheet P with a predetermined pressure.

In this case, the mutual relationships between the separation pawl 7, the spring 6, and the feed roller 10 is almost constant and the force W given to the separation pawl 7 can be maintained almost constant all the time, regardless of the stack thickness of the cut sheet P, if the design is made to satisfy the formula where C weight per unit load thickness when the maximum specified number of sheets are loaded and C spring constant. The free length I, of the spring 6 is given by where W weight of the feed roller 10, W weight of the intermediate plate, and Ly length of the compressed spring when no cut sheet is loaded.

Therefore, when the feed roller 10 rotates upon receiving a feed signal, the uppermost cut sheet P is sent out and the separation pawl 7 prevents two or more sheets from being sent out. When the cut sheets are gradually reduced in number by consumption, the intermediate plate 5 is pushed up at the front side first by the spring 6 thereby pivoting around the rear end supporting point 12. Thus, regardless of the reduction in the number of cut sheets P, because the pressing force against the separation pawl 7 is designed to be almost constant as mentioned above, automatic feeding of the final sheet is made under the same conditions as the feeding of the first sheet.

Because the intermediate plate 5 inclines around the rear supporting point 12, with an increase in its inclination as the sheets are consumed the gap between its front end and the front wall 2 of the cassette box becomes wider and the area by which the top sheet P makes contact with the separation pawl 7 becomes narrower. This may disturb the paper feeding and may delay the feed timing by the amount of the gap.

In order to avoid such dangers, it is desirable to bend the rear end of the intermediate plate 5 upwardly in an L shape of suitable dimension so that the upper edge of the L shaped bent section 5 descends along the rear wall of the cassette box 2 and slides the intermediate plate 5 forwardly when the intermediate plate inclines.

Because the cassette device according to the invention maintains the cassette box immobile in the body of the copying device, the upward force of the cut sheets against the separation pawl on the cassette box caused by the spring acting on the intermediate plate, is always constant, regardless of the decrease in the supply of cut sheets:

. l. The cassette box is assuredly fixed to the body of the copying device and, because the fixing method is simple and sure, no compulsive force is applied to the separation pawls 7 by vibration or by carelessly pushing the box or by placing something on it, and the position of the cassette box in not altered.

In other words, the cassette means is very stable as compared to conventional, known configurations in which the intermediate plate for carrying the cut sheets is suspended by the support provided on the body of the copying device and the cassette box itself is made to move down, gradually;

2. Because the leading end of the cut sheet is always dispensed from the same position, the cassette can be placed immediately before the seizing rollers 11 and thus obviate the need for an auxiliary guide;

3. Even in the case where the cassette is removed from the copying device, the leading ends of the cut sheets are left seized by the separation pawls and never get out of place;

4. The pressing force applied to the separation pawls is suitably chosen and kept almost constant even when the number of cut sheets has been reduced. Thus the feeding condition is always constant.

In another embodiment of the invention, the intermediate plate for carrying the cut sheets is pushed up by springs near its four corners. This enables the maxi- I mum number of cut sheets loaded in the cassette to be where C the weight per unit load thickness when the maximum predetermined number of sheets are loaded and C the spring constant, the force W which is applied to the separation pawl can be always maintained substantially constant, regardless of the load thickness of cut sheets P. The free length L, of the spring 6 is tion pawls provided at the front corners of the cassette box and, simultaneously, the cut sheets are pressed against the ascent stopper, provided on the side wall of the rear end of the cassette box, with a force insufficient to disturb the paper feeding. By means of the action of the feed roller, the top positioned cut sheet is fed over the separation pawl. As the number of cut sheets increases due to consumption, the intermediate plate is pushed up so as to always maintain uniform contact pressure between the cut sheets and the separation pawls. I

However, instead of using the two push-up springs at the rear end, one push-up spring positioned at the center can be used.

This invention will be described in more detail with reference to the embodiment shown in FIGS. 4 through 6, in which, 1 is the cassette holder in the copying device, 2 is the cassette box which can be detachably set on the receiver 4 of the holder 1 by three or four legs, in its correct position. The inside of the cassette box 2 has suitable dimensions with proper margins corresponding to the length and width of the cut sheets P and is made deeper than the thickness of the stack of a predetermined number of cut sheets which are to be loaded. The intermediate plate 5 is placed in the box 2 so as to be free to move vertically, and the spring 6 is provided between the under surface of the front part of the intermediate plate, taken in the feeding direction, and the box 2, and simultaneously the spring 6' is provided at the rear to press the front end corners of cut sheets up to the separation pawls 7 on the front corners of the cassette box. At this time, the rear end part of the cut sheets is prevented by the ascent stopper 13 from moving up through the cassette box. The cassette box 2 has a lid 8. A front lid 8 is opened by means of a hinge 9, after the box has been loaded in the copying device, to provide access for the feed roller 10 to the top cut sheet. There is also provided sheet seizing roller 11.

In the above-mentioned configuration, a predetermined number of cut sheets P are loaded into the cassette box 2 between the separation pawls 7, the ascent stopper 13 and the intermediate plate by compressing the springs 6 and 6.

When this cassette box 2 is set to the fixed position on the holder 1 of the copying device as shown in FIG. 5, the separation pawls 7 at its front end take a predetermined position relative to the seizing rollers 11 and the feed roller 10 also makes contact with the top positioned cut sheet P with a predetermined pressure.

In this case, the mutual relationship between the separation pawls 7, spring 6, and feed roller 10 is almost settled, and by designing the relationship so as to satisfy the formula given by where W weight of the feed roller 10, W weight of the intermediate plate, and Ly length of the compressed spring when no cut sheets are present. Similarly, by designing the relationship so that where C spring constant of the spring 6', the force W applied to the ascent stopper 13 can be maintained almost constant. However, these calculations were made by assuming that the spring 6 and feed roller 10 are sufficiently close to the leading end of the cut sheet and that the spring 6' is also sufficiently close to the rear end of the cut sheet.

When the feed roller 10 rotates upon receiving a feed signal, the cut sheet P at the highest position is sent out and the separation pawls prevents additional cut sheets from being sent out. When the number of cut sheets decreases gradually due to consumption, the intermediate plate 5 is pushed up by the springs 6 and 6'. And, because the pressing forces against the separation pawls 7 and ascent stopper 13 are designed to be almost constant and independent of the reduction in the cut sheets P, automatic feeding is performed under the same con ditions down to the, last sheet.

Thus, the cassette device of this invention keeps the cassette box set on the body of the copying device immobile and presses the cut sheets against the separation pawls and ascent stopper of the cassette box by gradually pushing up the intermediate plate, which is placed in the cassette box, and always maintains constant pressing forces, independent of the reduction in the number of cut sheets.

Another embodiment is shown in FIGS. 7 through 10. The top side of the container box 2 is open, and the feeding side, lateral side 45 is made separately from the body of the box. Arms 45 are provided at right angles at both ends of the lateral side 45 and it is loosely mounted to the body of the box through shafts 45 A separation pawl 45 is provided on each end of the upper side of the lateral side 45 facing inwardly, and the lower side 45 is bent along the lower surface of the bottom of the body 2 and the bottom 2 of the body is inserted into the space between the lower side 45 and the bottom of the arm 45 to prevent the separation pawls 45 from moving beyond a certain degree. Ascent stopper 13 of the sheet is provided at the comer of the rear end (on the opposite side from the feeding side) of the box body 2.

7 An intermediate plate 43, which is slightly smaller in demensions than the inside dimensions of the box body, is placed in the box 2, and a flat spring (or a coil spring) 44 is provided between the intermediate plate and the bottom 2 The spring 44 is of sufficient strength to push up a predetermined number of sheets of paper P via the intermediate plate 43 and to press the paper P against the separation pawls 45 and ascent stopper 13 with a suitable force, even when the amount of paper has been reduced by consumption. In this case the bent edge 45;, of the bottom of the lateral side 45 is in contact with the back of the bottom 2 of the body, as shown in FIG. 8. When the number of sheets loaded and contained is small, it is only necessary to push up the feeding side of the intermediate plate 43 to incline plate, leaving its rear end in contact with the bottom 2 of the box. 7

The feed roller 46 is supported by the arm 134 which is provided with a shaft 120. The arm 134 is coupled to the feed lever 133 by, for example, a pin 134 mounted in a elongated hole 133,. The roller 46 is positioned spaced apart from the paper face in the box by the spring 134 and rotates either continuously or rotates only at the time of feeding the paper.

When, by the feed signal, the shaft 131 and lever 133 rotate clockwise by a fixed angle, the arm 134 rotates counterclockwise by a fixed angle to press the roller 46 against the upper face of the loaded paper P. The lower position of the roller 46 is always constant and, at this time, the lower end face of the roller is so set as to be slightly below the natural position of the top-positioned copying paper P which has been pushed up by the spring 44. Therefore, the roller 46 first makes contact with the uppermost copying paper and then comes down to the predetermined position by pressing down the copying paper, against the spring 44, and feeds the paper by its own rotation.

During this time, the separation pawls 45 go down around the shaft 45 caused by the weight of the entire lateral side 45 with the descent of the copying paper P, and further, since the hole on the box body, which corresponds to the shaft 45 is oblong in the vertical direction (oval hole), the separation pawls on both ends make contact with the copying paper P without being forced, and accordingly the separation pawls 14 press the copying paper P by their own weight. Therefore the separating action is always the same even when the amount of the paper has been reduced and thus the paper is fed assuredly, one sheet at a time.

Because this invention has the above-mentioned configuration, the dispensing position of the copying paper is invariable regardless of the amount of the paper, and the feed guides 48, and 48 can be made small and compact.

As the separation pawls 45 press the paper with a constant pressure due to their own weight regardless of the amount of the paper, the separating action is effected without fail. The configuration, in which the spring 44 pushes up the paper when the amount of copying paper has been reduced, serves only to compensate for the change in the height of the upper surface of the copying paper.

The device of the present invention is simple and stable as compared with the prior art devices in which the paper was supported by an intermediate plate and, as the paper decreased the body of the box was lowered.

In the drawing, 8 and 3 show a lid for preventing dust and light from entering into the cassette. At time g of use, the snatch lid 8 is opened and can be made to serve as the tray for copied paper coming from the main unit.

Next, a cassette means which also serves as a tray will be described, referring to FIGS. 11 through 21.

FIG. 1 1 shows a small-sized cassette means 2 is mounted on the body 1 of a copying device. FIG. 12 shows a large-sized cassette means 2 mounted on the body of a copying device. As shown in the left end view FIG. 13, and the partially magnified end view in FIG. 4, the cassette 2 is provided with a rail-shaped projection 21 on the front and rear surfaces and is guided by the rail 154 when being mounted or detached. The lid of the cassette 2 is divided into two parts, a fixed lid 8 and a movable lid 8 both lids being coupled by means of a hinge 9. When the movable lid 8 is opened and reversed and placed on the fixed lid 8, a part of the movable lid projects rearwardly from the cassette 2 to form a copy tray, as shown in FIGS. 15 and 16. The free end bent edge 81 of the movable lid 8 serves as a lid covering the lateral side of the cassette and as a copy stopper when the lid is converted to a tray.

In FIG. 16, two lids 8 and 8, are overiayed at portion l, which is opened when the movable lid 8, is opened, and there the feed roller 46 acts on the sheet 1 The distance between the copy discharge port 62 of the copying device body 15 and the stopper 8, of the copy tray is determined by the position of the hinge 9 of the movable hinge 81 for each size of cassette to correspond to the length of each size of copying paper.

In FIGS. 11 and 12 where there is a big difference in height between the positions of the discharge port 62 and the cassette 2, an auxiliary tray 14 is attached to the body of copying device to form a copy tray together with the lid tray 81. To make use of the auxiliary tray 2% in such a way that it can be removed when part 62 and lid 8 are positioned close to each other is an effective means in the design, because it offers a great deal of freedom in the layout of the cassette.

FIG. 18 shown a projection 8 and mating groove 2,, which are used to hinge the fixed lid 8 to the cassette 2. Thus, the lid 8 is fixed to the cassette by 8 2 and the front bent edge 8 When the cassette 2 is mounted in its predetermined position on the body 15., the cam 2 on the back of the cassette pushes the switch M319 on the body and transmits a load signal. Holes 43 and 2 penetrate through the intermediate plate 43 and the bottom plate of the cassette and, by the function of photoelectric unit 155 and 156., a signal is issued when the cassette is empty of copying paper. On the back of the cassette for sizes A4 or less, a cam 2 (FIGS. 19 and 20) is provided which serves to change-over the machine cycle to A4 copy cycle by depressing the switches M813 and MS16. On the back of the cassettes larger than that for size A4, no such cam acting on the abovementioned switches MS 13 and M816 is present (FiGS. 15 and 16) and the machine operates in an A3 copy cycle. In the drawing, 46 is the feed roller, and 45 in FIG. 20 is the sheet separation pawl.

Next, an example of a cassette will be described in which the feed side lateral side 46 of the cassette 2 is made separately from the box of the cassette body, and a separation pawl 45 is provided on each upper end of the lateral side 46 The side 46 is made to move vertically with respect to the body box by means of the arm 45;, and shaft 45 so that, when the loaded paper P is pushed down to a predetermined position by the feed roller 46, the separation 45 and the lateral side 46 follow the paper P by virtue of their own weight.

Another embodiment of the invention is shown in FIGS. 22 through 25. Although the cassette is so designed that the paper load in the cassette is pushed down a certain degree by the feed roller, the separation pawl also lowers itself by its own weight, and by the joint action of the revolution of the feed roller and the separation pawl, one sheet of paper is separated and sent out to the body. However, in order to assure the one sheet separation, an auxiliary means is provided in practical use. In this invention, the lateral side parallel to the feed direction is lightly pressed by using sponging plastic etc. This is called the side presser 17. In order to be sure to press the side of the paper, the above-mentioned side presser 17 is positioned inside the paper width at its free position.

The paper pressing part of each of the pair of side pressers shown in FIG. 25 receives the force from the spring 18 to improve the effect when the paper is loaded. In FIG. 25 the side presser 17 is pressed by the spring to the position shown by an alternate long and two short dashes line. At this time, the interval between the pair of side presser 17 is narrower than the paper width and the upper section 16 of the side presser is inclined. Due to this inclination, the side presser 17 receives a force opposite to the force of spring 18 and is moved in the direction of the arrow when the paper is loaded from above the side presser 17. When the paper loading is finished, presser presses the lateral side of the paper with assurance by the force of the spring. Accordingly, there is no need of moving the side presser by hand when loading paper and, thus, the merit of the cassette system is fully displayed.

We claim:

I. An automatic cut sheet feeding unit comprising in combination,

a box type body, said box type body comprising a separation pawl on top of each forward comer section thereof, the separation pawl being movable between a fixed upper and variable lower positions relative to the box type body,

an intermediate plate which carries a stack of 'cut sheets and is accommodated in the box type body,

spring means between the box type body and the intermediate plate and used to press the cut sheets loaded on the intermediate plate against the bottom face of the separation pawls in the fixed upper position,

a feed roller mounted to be movable between a position out of contact with the stack, in which position the spring means urges the stack against the pawl and forces the pawl to its fixed upper position and 10 a feeding position in pressure contact with the stack and below the upper fixed position of the pawl so that the pawl rests against the stack by its own weight,

said feed roller, on receiving a feed signal, feeding the cut sheets loaded on the intermediate plate,

and means to drive and control the feed roller.

2. An automatic cut sheet feeding unit as set forth in claim 1, wherein the spring means is installed at the end of the paper feeding side between the. intermediate plate and the box type body.

3. An automatic cut sheet feeding unit as set forth in claim 1, wherein the spring means is installed in between the box type body and the intermediate plate to push up the intermediate plate horizontally.

4. An automatic cut sheet feeding unit as set forth in claim 1, wherein the box type body possesses a fixed lid and movable lid and, means mounting said box type body and its movable lid on a copying device for said movable lid to serve as a tray for the copied paper.

5. An automatic cut sheet feeding unit as set forth in claim 1, wherein the box type body so composed as to be provided with a side presser on each lateral side when facing the paper feeding direction and a spring used to place the side pressers in positions spaced by a distance narrower than the width of the cut sheet, and the side pressers have a slope at the upper section thereof so as to allow the cut sheets to be inserted and loaded automatically.

6. An automatic cut sheet feeding unit comprising in combination:

a box type body,

a separation pawl adjacent each forward corner section thereof and free to move substantially, vertically relative to said box type body,

an intermediate plate accommodated in the box type body for carrying cut sheets thereon, said separation pawls bearing against the upper surface of the cut sheets with a constant pressure,

resilient means operative against said intermediate plate to urge said plate in a direction to press the uppermost of the cut sheets loaded on the intermediate plate towards a discharge position,

a feed roller mounted above the cut sheets to cooperate with said resilient means to exert a pressure upon the upper surface of the cut sheets at the discharge position,

said feed roller operative upon receiving a feed signal, to feed the uppermost cut sheet loaded on the intermediate plate, and

means to drive and control said feed roller.

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,919,972 Dated November 18, 1975 Inventor(s) SHIGEHIRO KOMORI et al.

It is certified that error appears in the above-identified patent G and that said Letters Patent are hereby corrected as shown below:

Column 1, line 54, after "and" insert it Column 5, line 19, change "increases" to decreases Column 6, line 36, change "prevents" to prevent Column 10, line 21, change "paper" to sheets a line 24, change "paper" to cut sheet Signed and Sealed this G seventeenth Day Of February 1976 [SEAL] Attest:

RUTH. C. MSON C. MARSHALL DANN Arresting Officer Commissioner nfParenIs and Trademarks 

1. An automatic cut sheet feeding unit comprising in combination, a box type body, said box type body comprising a separation pawl on top of each forward corner section thereof, the separation pawl being movable between a fixed upper and variable lower positions relative to the box type body, an intermediate plate which carries a stack of cut sheets and is accommodated in the box type body, spring means between the box type body and the intermediate plate and used to press the cut sheets loaded on the intermediate plate against the bottom face of the separation pawls in the fixed upper position, a feed roller mounted to be movable between a position out of contact with the stack, in which position the spring means urges the stack against the pawl and forces the pawl to its fixed upper position and a feeding position in pressure contact with the stack and below the upper fixed position of the pawl so that the pawl rests against the stack by its own weight, said feed roller, on receiving a feed signal, feeding the cut sheets loaded on the intermediate plate, and means to drive and control the feed roller.
 2. An automatic cut sheet feeding unit as set forth in claim 1, wherein the spring means is installed at the end of the paper feeding side between the intermediate plate and the box type body.
 3. An automatic cut sheet feeding unit as set Forth in claim 1, wherein the spring means is installed in between the box type body and the intermediate plate to push up the intermediate plate horizontally.
 4. An automatic cut sheet feeding unit as set forth in claim 1, wherein the box type body possesses a fixed lid and movable lid and, means mounting said box type body and its movable lid on a copying device for said movable lid to serve as a tray for the copied paper.
 5. An automatic cut sheet feeding unit as set forth in claim 1, wherein the box type body so composed as to be provided with a side presser on each lateral side when facing the paper feeding direction and a spring used to place the side pressers in positions spaced by a distance narrower than the width of the cut sheet, and the side pressers have a slope at the upper section thereof so as to allow the cut sheets to be inserted and loaded automatically.
 6. An automatic cut sheet feeding unit comprising in combination: a box type body, a separation pawl adjacent each forward corner section thereof and free to move substantially, vertically relative to said box type body, an intermediate plate accommodated in the box type body for carrying cut sheets thereon, said separation pawls bearing against the upper surface of the cut sheets with a constant pressure, resilient means operative against said intermediate plate to urge said plate in a direction to press the uppermost of the cut sheets loaded on the intermediate plate towards a discharge position, a feed roller mounted above the cut sheets to cooperate with said resilient means to exert a pressure upon the upper surface of the cut sheets at the discharge position, said feed roller operative upon receiving a feed signal, to feed the uppermost cut sheet loaded on the intermediate plate, and means to drive and control said feed roller. 